This invention relates to a printer or printing apparatus employing a daisy-type type wheel and, more particularly, to structure of the daisy-type type wheel and a mounting mechanism thereof.
Many disclosures relate to the structure of the daisy-type type wheel and the mounting or loading mechanism of this kind of type wheel to the printer are known, such as U.S. Pat. No. 4,049,110, U.S. Pat. No. 4,124,312, and U.S. Pat. No. 4,127,335.
Those prior art devices all have problems, in having either a structure wherein the operator himself must manually align the home position of a drive shaft for the type wheel supported by the printer with the home position of the type wheel, or another structure wherein positioning in the direction of rotation between the drive shaft and the type wheel must be done by locking the drive shaft at a predetermined position by a locking device while on the other hand by maintaining the type wheel at a predetermined position in the rotational direction relatively to a type wheel cartridge containing the type wheel by another locking device disposed therebetween.
In the former type structure positioning of the type wheel when it is mounted or loaded is not only troublesome for the operator but also likely to cause damage to it due to an operator's mistake resulting from the troublesome handling. The latter structure is, notwithstanding of its improvement in having eliminated the defect in the former, not free from another problem such that each of the printer, the cartridge and the type wheel has to be provided with a structure or means related to the above-mentioned two locking devices, leading naturally to complication in structure and increase of the manufacturing cost.